Temporal And Spatial Variation Of Regional Impervious Surface And Its Impact On Eco-environmental Quality

With the development of economy and society,there are more and more impervious buildings in cities.Because the impervious building materials have unique characteristics,the increase of impervious surface will have an impact on the urban ecological environment.Xiamen is an important central city along the southeast coast.Its regional location conditions are special.It is of great significance to explore the temporal and spatial evolution law of impervious surface and the change of ecological environment effect.In this paper,the linear spectral hybrid decomposition technology(LSMA)is used to extract the impervious surface information of Xiamen City from 2003to 2019 based on multi-phase Landsat series remote sensing data,quantitatively analyze the evolution process of impervious surface with time and space,analyze the change process of urban surface impervious surface from different scales of the whole city and various regions within the city,and reveal the expansion characteristics of the city;Based on the new remote sensing ecological index(RSEI),this paper studies the impact of impervious surface change on regional ecological environment quality,and explores the correlation between various modeling factors and ecological environment quality and threshold diagnosis,so as to provide a more detailed scientific reference for urban development and ecological environment research.The main results are as follows:(1)Using LSMA to extract the impervious surface information,it is found that the impervious surface in Xiamen expanded significantly from 2003 to 2019.On the time scale,the intensive use of urban land increases,and the impervious surface aggregation effect appears:the impervious surface expansion speed of Tong’an District and Jimei District is greater in the early stage of the study,while the impervious surface expansion speed of Huli district is faster in the later stage,and the expansion speed of Siming District decreases first and then increases.On the spatial scale,the development direction of impervious surface in each administrative region is different:the center of gravity of impervious surface in Xiamen Island is relatively stable;The gravity center of impervious surface in Haicang District continues to move northward;The center of gravity of impervious surface area in Jimei District moves to the northwest;The expansion direction of impervious surface in Tong’an District first moves to the southwest and then moves back to the northeast;The center of gravity in Xiang’an District first moves north by West and then southeast.(2)Select RSEI to objectively evaluate the eco-environmental quality.The research shows that the eco-environmental quality of the study area decreased from 2003 to 2019.The area where RSEI decreased reached 371.56)8)~2,accounting for 24.16%of the total area,and the area where eco-environmental quality improved accounted for 18.47%of the total area.Then explore the impact of the change of impervious surface on the quality of ecological environment.It is found that the increase of regional impervious surface will lead to the decline of regional RSEI value,that is,reduce the quality of regional ecological environment.Vegetation can alleviate the decline of ecological environment quality to a certain extent.If the area of medium density and above types of impervious surface continues to increase,the drastic changes in regional ecological environment quality caused by it will have a great impact on the overall ecological environment quality of the study area.(3)This paper introduces the relevant indicators in the ecological landscape pattern,analyzes the ecological environment quality of impervious surface from the interior of urban landscape,and puts forward a comprehensive modeling factor index(CMF).Among the modeling factors,the most significant correlation with RSEI is the coverage index(PLAND),and the least influence on RSEI is the average patch fractal dimension(MPFD);The factors that have a positive effect on the urban ecological environment are patch density(PD)and dispersion index(Division),while the modeling factors such as PLAND,average patch area(Area＿MN),area weighted average patch fractal index(AWMPFD)and aggregation index(AI)have a negative correlation with RSEI.The comprehensive modeling factor index CMF decreases with the increase of impervious surface coverage,aggregation and dispersion,and increases when the average patch area of impervious surface increases.(4)For different impervious surface construction areas,different measures can be taken to improve the quality of ecological environment:in low-density construction areas,it is necessary to reasonably balance the aggregation and dispersion of buildings Area＿MN should not be too high,PD value should be controlled above 8.5,and impervious patches should be as simple and regular as possible,and AWMPFD value should be kept below 1.31;In the middle and low density construction area,the coverage of impervious patches should be controlled,and the buildings should not gather;In the medium density construction area,the aggregation effect of impervious surface should be avoided as far as possible,and the PD value should be kept above 36.3;In the high-density construction area,the AI value should be less than 79.9 and the Division should be greater than 0.38,and the building boundary contour should be expanded to increase the contact space with the permeable surface and keep the AWMPFD above 1.38.